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<tr class="t-nv"><td colspan="5"> <a href="iterator.html" title="cpp/header/iterator"><tt>&lt;iterator&gt;</tt></a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> 范围</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ranges.html" title="cpp/header/ranges"><tt>&lt;ranges&gt;</tt></a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> 算法</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="algorithm.html" title="cpp/header/algorithm"><tt>&lt;algorithm&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="execution.html" title="cpp/header/execution"><tt>&lt;execution&gt;</tt></a></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> 数值</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="complex.html" title="cpp/header/complex"><tt>&lt;complex&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="random.html" title="cpp/header/random"><tt>&lt;random&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="valarray.html" title="cpp/header/valarray"><tt>&lt;valarray&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="numeric.html" title="cpp/header/numeric"><tt>&lt;numeric&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="bit.html" title="cpp/header/bit"><tt>&lt;bit&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="numbers.html" title="cpp/header/numbers"><tt>&lt;numbers&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="cfenv.html" title="cpp/header/cfenv"><tt>&lt;cfenv&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="cmath.html" title="cpp/header/cmath"><tt>&lt;cmath&gt;</tt></a></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> 输入/输出</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="iosfwd.html" title="cpp/header/iosfwd"><tt>&lt;iosfwd&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ios.html" title="cpp/header/ios"><tt>&lt;ios&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="iomanip.html" title="cpp/header/iomanip"><tt>&lt;iomanip&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="streambuf.html" title="cpp/header/streambuf"><tt>&lt;streambuf&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="istream.html" title="cpp/header/istream"><tt>&lt;istream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ostream.html" title="cpp/header/ostream"><tt>&lt;ostream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="iostream.html" title="cpp/header/iostream"><tt>&lt;iostream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="sstream.html" title="cpp/header/sstream"><tt>&lt;sstream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="fstream.html" title="cpp/header/fstream"><tt>&lt;fstream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="syncstream.html" title="cpp/header/syncstream"><tt>&lt;syncstream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="cstdio.html" title="cpp/header/cstdio"><tt>&lt;cstdio&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="cinttypes.html" title="cpp/header/cinttypes"><tt>&lt;cinttypes&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="strstream.html" title="cpp/header/strstream"><tt>&lt;strstream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> 正则表达式</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="regex.html" title="cpp/header/regex"><tt>&lt;regex&gt;</tt></a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> 文件系统</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="filesystem.html" title="cpp/header/filesystem"><tt>&lt;filesystem&gt;</tt></a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> 线程支持</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="thread.html" title="cpp/header/thread"><tt>&lt;thread&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="atomic.html" title="cpp/header/atomic"><tt>&lt;atomic&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="mutex.html" title="cpp/header/mutex"><tt>&lt;mutex&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="shared_mutex.html" title="cpp/header/shared mutex"><tt>&lt;shared_mutex&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="condition_variable.html" title="cpp/header/condition variable"><tt>&lt;condition_variable&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <strong class="selflink"><tt>&lt;future&gt;</tt></strong></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="stop_token.html" title="cpp/header/stop token"><tt>&lt;stop_token&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="semaphore.html" title="cpp/header/semaphore"><tt>&lt;semaphore&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="latch.html" title="cpp/header/latch"><tt>&lt;latch&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="https://zh.cppreference.com/mwiki/index.php?title=cpp/header/barrier&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/barrier（页面不存在）"><tt>&lt;barrier&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> C 兼容</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="ciso646.html" title="cpp/header/ciso646"><tt>&lt;ciso646&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="cstdalign.html" title="cpp/header/cstdalign"><tt>&lt;cstdalign&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="cstdbool.html" title="cpp/header/cstdbool"><tt>&lt;cstdbool&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ccomplex.html" title="cpp/header/ccomplex"><tt>&lt;ccomplex&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="ctgmath.html" title="cpp/header/ctgmath"><tt>&lt;ctgmath&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td></tr>
</table></div><div></div></div></div></div><div class="t-navbar-sep"> </div></div>
<p>此头文件是<a href="../thread.html" title="cpp/thread">线程支持</a>库的一部分。
</p>
<table class="t-dsc-begin">

<tr>
<td colspan="2"> <h3> <span class="mw-headline" id=".E7.B1.BB">类</span></h3>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/promise.html" title="cpp/thread/promise"> <span class="t-lines"><span>promise</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>  存储一个值以进行异步获取 <br> <span class="t-mark">(类模板)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/packaged_task.html" title="cpp/thread/packaged task"> <span class="t-lines"><span>packaged_task</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>  打包一个函数，存储其返回值以进行异步获取 <br> <span class="t-mark">(类模板)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/future.html" title="cpp/thread/future"> <span class="t-lines"><span>future</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>  等待被异步设置的值 <br> <span class="t-mark">(类模板)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/shared_future.html" title="cpp/thread/shared future"> <span class="t-lines"><span>shared_future</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>  等待被异步设置的值（可能为其他 future 所引用） <br> <span class="t-mark">(类模板)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/launch.html" title="cpp/thread/launch"> <span class="t-lines"><span>launch</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>  指定 <span class="t-lc"><a href="../thread/async.html" title="cpp/thread/async">std::async</a></span> 所用的运行策略 <br> <span class="t-mark">(枚举)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/future_status.html" title="cpp/thread/future status"> <span class="t-lines"><span>future_status</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>  指定在 <span class="t-lc"><a href="../thread/future.html" title="cpp/thread/future">std::future</a></span> 和 <span class="t-lc"><a href="../thread/shared_future.html" title="cpp/thread/shared future">std::shared_future</a></span> 上的定时等待的结果 <br> <span class="t-mark">(枚举)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/future_error.html" title="cpp/thread/future error"> <span class="t-lines"><span>future_error</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>  报告与 future 或 promise 有关的错误 <br> <span class="t-mark">(类)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/future_errc.html" title="cpp/thread/future errc"> <span class="t-lines"><span>future_errc</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>  鉴别 future 错误码 <br> <span class="t-mark">(枚举)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/promise/uses_allocator.html" title="cpp/thread/promise/uses allocator"> <span class="t-lines"><span>std::uses_allocator<span class="t-dsc-small">&lt;std::promise&gt;</span></span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   特化 <span class="t-lc"><a href="../memory/uses_allocator.html" title="cpp/memory/uses allocator">std::uses_allocator</a></span> 类型特征  <br> <span class="t-mark">(类模板特化)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/packaged_task/uses_allocator.html" title="cpp/thread/packaged task/uses allocator"> <span class="t-lines"><span>std::uses_allocator<span class="t-dsc-small">&lt;std::packaged_task&gt;</span></span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span><span class="t-mark-rev t-until-cxx17">(C++17 前)</span></span></span></div></div>
</td>
<td>   特化 <span class="t-lc"><a href="../memory/uses_allocator.html" title="cpp/memory/uses allocator">std::uses_allocator</a></span> 类型特征  <br> <span class="t-mark">(类模板特化)</span> </td></tr>

<tr>
<td colspan="2"> <h3> <span class="mw-headline" id=".E5.87.BD.E6.95.B0">函数</span></h3>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/async.html" title="cpp/thread/async"> <span class="t-lines"><span>async</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>  异步运行一个函数（有可能在新线程中执行），并返回保有其结果的 <span class="t-lc"><a href="../thread/future.html" title="cpp/thread/future">std::future</a></span>  <br> <span class="t-mark">(函数模板)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/future/future_category.html" title="cpp/thread/future category"> <span class="t-lines"><span>future_category</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   鉴别 future 错误类别 <br> <span class="t-mark">(函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/promise/swap2.html" title="cpp/thread/promise/swap2"> <span class="t-lines"><span>std::swap<span class="t-dsc-small">(std::promise)</span></span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   特化 <span class="t-lc"><a href="../algorithm/swap.html" title="cpp/algorithm/swap">std::swap</a></span> 算法 <br> <span class="t-mark">(函数模板)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/packaged_task/swap2.html" title="cpp/thread/packaged task/swap2"> <span class="t-lines"><span>std::swap<span class="t-dsc-small">(std::packaged_task)</span></span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   特化 <span class="t-lc"><a href="../algorithm/swap.html" title="cpp/algorithm/swap">std::swap</a></span> 算法 <br> <span class="t-mark">(函数模板)</span> </td></tr>
</table>
<h3><span class="mw-headline" id=".E6.A6.82.E8.A6.81">概要</span></h3>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
    <span class="kw2">enum</span> <span class="kw1">class</span> future_errc <span class="br0">{</span>
        broken_promise <span class="sy1">=</span> <span class="coMULTI">/* 由实现定义 */</span>,
        future_already_retrieved <span class="sy1">=</span> <span class="coMULTI">/* 由实现定义 */</span>,
        promise_already_satisfied <span class="sy1">=</span> <span class="coMULTI">/* 由实现定义 */</span>,
        no_state <span class="sy1">=</span> <span class="coMULTI">/* 由实现定义 */</span>
    <span class="br0">}</span><span class="sy4">;</span>
 
    <span class="kw2">enum</span> <span class="kw1">class</span> launch <span class="sy4">:</span> <span class="coMULTI">/* 未指明 */</span> <span class="br0">{</span>
        async <span class="sy1">=</span> <span class="coMULTI">/* 未指明 */</span>,
        deferred <span class="sy1">=</span> <span class="coMULTI">/* 未指明 */</span>,
        <span class="coMULTI">/* 由实现定义 */</span>
    <span class="br0">}</span><span class="sy4">;</span>
 
    <span class="kw2">enum</span> <span class="kw1">class</span> future_status <span class="br0">{</span>
        ready,
        timeout,
        deferred
    <span class="br0">}</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;&gt;</span>
    <span class="kw1">struct</span> is_error_code_enum<span class="sy1">&lt;</span>future_errc<span class="sy1">&gt;</span> <span class="sy4">:</span> <span class="kw1">public</span> true_type <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
 
    error_code make_error_code<span class="br0">(</span>future_errc e<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    error_condition make_error_condition<span class="br0">(</span>future_errc e<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">const</span> error_category<span class="sy3">&amp;</span> future_category<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    <span class="kw1">class</span> future_error<span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span> <span class="kw1">class</span> promise<span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span> <span class="kw1">class</span> promise<span class="sy1">&lt;</span>R<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;&gt;</span> <span class="kw1">class</span> promise<span class="sy1">&lt;</span><span class="kw4">void</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    <span class="kw4">void</span> swap<span class="br0">(</span>promise<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, promise<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> Alloc<span class="sy1">&gt;</span>
    <span class="kw1">struct</span> uses_allocator<span class="sy1">&lt;</span>promise<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, Alloc<span class="sy1">&gt;</span> <span class="sy4">:</span> true_type <span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span> <span class="kw1">class</span> future<span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span> <span class="kw1">class</span> future<span class="sy1">&lt;</span>R<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;&gt;</span> <span class="kw1">class</span> future<span class="sy1">&lt;</span><span class="kw4">void</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span> <span class="kw1">class</span> shared_future<span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span> <span class="kw1">class</span> shared_future<span class="sy1">&lt;</span>R<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;&gt;</span> <span class="kw1">class</span> shared_future<span class="sy1">&lt;</span><span class="kw4">void</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span><span class="sy1">&gt;</span> <span class="kw1">class</span> packaged_task<span class="sy4">;</span> <span class="co1">// 不予定义</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span>... <span class="me1">ArgTypes</span><span class="sy1">&gt;</span>
    <span class="kw1">class</span> packaged_task<span class="sy1">&lt;</span>R<span class="br0">(</span>ArgTypes...<span class="br0">)</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    <span class="kw4">void</span> swap<span class="br0">(</span>packaged_task<span class="sy1">&lt;</span>R<span class="br0">(</span>ArgTypes...<span class="br0">)</span><span class="sy1">&gt;</span><span class="sy3">&amp;</span>,
              packaged_task<span class="sy1">&lt;</span>R<span class="br0">(</span>ArgTypes...<span class="br0">)</span><span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> Alloc<span class="sy1">&gt;</span>
    <span class="kw1">struct</span> uses_allocator<span class="sy1">&lt;</span>packaged_task<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, Alloc<span class="sy1">&gt;</span> <span class="sy4">:</span> true_type <span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span>
     future<span class="sy1">&lt;</span>result_of_t<span class="sy1">&lt;</span>decay_t<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span><span class="br0">(</span>decay_t<span class="sy1">&lt;</span>Args<span class="sy1">&gt;</span>...<span class="br0">)</span><span class="sy1">&gt;&gt;</span>
     async<span class="br0">(</span>F<span class="sy3">&amp;&amp;</span> f, Args<span class="sy3">&amp;&amp;</span>... <span class="me1">args</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span>
     future<span class="sy1">&lt;</span>result_of_t<span class="sy1">&lt;</span>decay_t<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span><span class="br0">(</span>decay_t<span class="sy1">&lt;</span>Args<span class="sy1">&gt;</span>...<span class="br0">)</span><span class="sy1">&gt;&gt;</span>
     async<span class="br0">(</span>launch policy, F<span class="sy3">&amp;&amp;</span> f, Args<span class="sy3">&amp;&amp;</span>... <span class="me1">args</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id=".E7.B1.BB_std::future_error">类 <span class="t-lc"><a href="../thread/future_error.html" title="cpp/thread/future error">std::future_error</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">class</span> future_error <span class="sy4">:</span> <span class="kw1">public</span> logic_error <span class="br0">{</span>
 <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">explicit</span> future_error<span class="br0">(</span>error_code ec<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// C++17 前仅用于阐释</span>
    <span class="kw4">const</span> error_code<span class="sy3">&amp;</span> code<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">const</span> <span class="kw4">char</span><span class="sy2">*</span> what<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span></pre></div></div>
<h4><span class="mw-headline" id=".E7.B1.BB_std::promise">类 <span class="t-lc"><a href="../thread/promise.html" title="cpp/thread/promise">std::promise</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
<span class="kw1">class</span> promise <span class="br0">{</span>
 <span class="kw1">public</span><span class="sy4">:</span>
    promise<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> Allocator<span class="sy1">&gt;</span>
    promise<span class="br0">(</span>allocator_arg_t, <span class="kw4">const</span> Allocator<span class="sy3">&amp;</span> a<span class="br0">)</span><span class="sy4">;</span>
    promise<span class="br0">(</span>promise<span class="sy3">&amp;&amp;</span> rhs<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    promise<span class="br0">(</span><span class="kw4">const</span> promise<span class="sy3">&amp;</span> rhs<span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span>
    ~promise<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// 赋值</span>
    promise<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span>promise<span class="sy3">&amp;&amp;</span> rhs<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    promise<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> promise<span class="sy3">&amp;</span> rhs<span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span>
    <span class="kw4">void</span> swap<span class="br0">(</span>promise<span class="sy3">&amp;</span> other<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    <span class="co1">// 取得结果</span>
    future<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> get_future<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// 设置结果</span>
    <span class="kw4">void</span> set_value<span class="br0">(</span><span class="coMULTI">/* 见说明 */</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">void</span> set_exception<span class="br0">(</span>exception_ptr p<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// 以延迟通知设置结果</span>
    <span class="kw4">void</span> set_value_at_thread_exit<span class="br0">(</span><span class="coMULTI">/* 见说明 */</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">void</span> set_exception_at_thread_exit<span class="br0">(</span>exception_ptr p<span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span></pre></div></div>
<h4><span class="mw-headline" id=".E7.B1.BB_std::future">类 <span class="t-lc"><a href="../thread/future.html" title="cpp/thread/future">std::future</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
<span class="kw1">class</span> future <span class="br0">{</span>
 <span class="kw1">public</span><span class="sy4">:</span>
    future<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    future<span class="br0">(</span>future <span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    future<span class="br0">(</span><span class="kw4">const</span> future<span class="sy3">&amp;</span> rhs<span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span>
    ~future<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    future<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> future<span class="sy3">&amp;</span> rhs<span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span>
    future<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span>future<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    shared_future<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> share<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// 取得值</span>
    <span class="coMULTI">/* 见说明 */</span> get<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// 用以检查状态的函数</span>
    <span class="kw4">bool</span> valid<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">void</span> wait<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> Rep, <span class="kw1">class</span> Period<span class="sy1">&gt;</span>
    future_status wait_for<span class="br0">(</span><span class="kw4">const</span> chrono<span class="sy4">::</span><span class="me2">duration</span><span class="sy1">&lt;</span>Rep, Period<span class="sy1">&gt;</span><span class="sy3">&amp;</span> rel_time<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> Clock, <span class="kw1">class</span> Duration<span class="sy1">&gt;</span>
    future_status wait_until<span class="br0">(</span><span class="kw4">const</span> chrono<span class="sy4">::</span><span class="me2">time_point</span><span class="sy1">&lt;</span>Clock, Duration<span class="sy1">&gt;</span><span class="sy3">&amp;</span> abs_time<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span></pre></div></div>
<h4><span class="mw-headline" id=".E7.B1.BB_std::shared_future">类 <span class="t-lc"><a href="../thread/shared_future.html" title="cpp/thread/shared future">std::shared_future</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
<span class="kw1">class</span> shared_future <span class="br0">{</span>
 <span class="kw1">public</span><span class="sy4">:</span>
    shared_future<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    shared_future<span class="br0">(</span><span class="kw4">const</span> shared_future<span class="sy3">&amp;</span> rhs<span class="br0">)</span><span class="sy4">;</span>
    shared_future<span class="br0">(</span>future<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    shared_future<span class="br0">(</span>shared_future<span class="sy3">&amp;&amp;</span> rhs<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    ~shared_future<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    shared_future<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> shared_future<span class="sy3">&amp;</span> rhs<span class="br0">)</span><span class="sy4">;</span>
    shared_future<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span>shared_future<span class="sy3">&amp;&amp;</span> rhs<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    <span class="co1">// 取得值</span>
    <span class="coMULTI">/* 见说明 */</span> get<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="co1">// 用以检查状态的函数</span>
    <span class="kw4">bool</span> valid<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">void</span> wait<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> Rep, <span class="kw1">class</span> Period<span class="sy1">&gt;</span>
    future_status wait_for<span class="br0">(</span><span class="kw4">const</span> chrono<span class="sy4">::</span><span class="me2">duration</span><span class="sy1">&lt;</span>Rep, Period<span class="sy1">&gt;</span><span class="sy3">&amp;</span> rel_time<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> Clock, <span class="kw1">class</span> Duration<span class="sy1">&gt;</span>
    future_status wait_until<span class="br0">(</span><span class="kw4">const</span> chrono<span class="sy4">::</span><span class="me2">time_point</span><span class="sy1">&lt;</span>Clock, Duration<span class="sy1">&gt;</span><span class="sy3">&amp;</span> abs_time<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span></pre></div></div>
<h4><span class="mw-headline" id=".E7.B1.BB_std::packaged_task">类 <span class="t-lc"><a href="../thread/packaged_task.html" title="cpp/thread/packaged task">std::packaged_task</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span><span class="sy1">&gt;</span> <span class="kw1">class</span> packaged_task<span class="sy4">;</span> <span class="co1">// 不予定义</span>
 
<span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span>... <span class="me1">ArgTypes</span><span class="sy1">&gt;</span>
<span class="kw1">class</span> packaged_task<span class="sy1">&lt;</span>R<span class="br0">(</span>ArgTypes...<span class="br0">)</span><span class="sy1">&gt;</span> <span class="br0">{</span>
 <span class="kw1">public</span><span class="sy4">:</span>
    <span class="co1">// 构造与析构</span>
    packaged_task<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> F<span class="sy1">&gt;</span>
    <span class="kw1">explicit</span> packaged_task<span class="br0">(</span>F<span class="sy3">&amp;&amp;</span> f<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> Allocator<span class="sy1">&gt;</span>
    <span class="kw1">explicit</span> packaged_task<span class="br0">(</span>allocator_arg_t, <span class="kw4">const</span> Allocator<span class="sy3">&amp;</span> a, F<span class="sy3">&amp;&amp;</span> f<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// C++17 前</span>
    ~packaged_task<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// 无复制</span>
    packaged_task<span class="br0">(</span><span class="kw4">const</span> packaged_task<span class="sy3">&amp;</span><span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span>
    packaged_task<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> packaged_task<span class="sy3">&amp;</span><span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span>
 
    <span class="co1">// 移动支持</span>
    packaged_task<span class="br0">(</span>packaged_task<span class="sy3">&amp;&amp;</span> rhs<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    packaged_task<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span>packaged_task<span class="sy3">&amp;&amp;</span> rhs<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    <span class="kw4">void</span> swap<span class="br0">(</span>packaged_task<span class="sy3">&amp;</span> other<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">bool</span> valid<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    <span class="co1">// 结果取得</span>
    future<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> get_future<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// 执行</span>
    <span class="kw4">void</span> operator<span class="br0">(</span><span class="br0">)</span><span class="br0">(</span>ArgTypes... <span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">void</span> make_ready_at_thread_exit<span class="br0">(</span>ArgTypes...<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">void</span> reset<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span></pre></div></div>

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